Method for creating electrically conductive elements for semiconductor device structures using laser ablation processes and methods of fabricating semiconductor device assemblies

ABSTRACT

A method for forming at least one conductive element is disclosed. Particularly, a semiconductor substrate, including a plurality of semiconductor dice thereon, may be provided and a dielectric layer may be formed thereover. At least one depression may be laser ablated in the dielectric layer and an electrically conductive material may be deposited thereinto. Also, a method for assembling a semiconductor die having a plurality of bond pads and a dielectric layer formed thereover to a carrier substrate having a plurality of terminal pads is disclosed. At least one depression may be laser ablated into the dielectric layer and a conductive material may be deposited thereinto for electrical communication between the semiconductor die and the carrier substrate. The semiconductor die may be affixed to the carrier substrate and at least one of the dielectric layer and the conductive material may remain substantially solid during affixation therebetween. The methods may be implemented at the wafer level.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 10/933,197,filed Sep. 1, 2004, now U.S. Pat. No. 7,575,999, issued Aug. 18, 2009.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the fabrication ofsemiconductor device structures. More particularly, the presentinvention relates to a method for creating depressions in asemiconductor substrate or film using laser ablation processes and usingsuch depressions for defining precise electrically conductive elementsalong selected pathways in a semiconductor device structure, as well asrelated methods of fabricating semiconductor device assemblies.

2. Background of the Related Art

Connection lines (e.g., lead and/or bond connections), traces, signalsand other elongated conductive elements are utilized in semiconductordevice structures to carry electronic signals and other forms ofelectron flow between one region of the semiconductor device structureand another region thereof and between regions within the semiconductordevice structure and external contacts (e.g., solder balls, bond padsand the like) associated therewith. Conventional methods for formingsuch elongated conductive elements may utilize a damascene processwherein one or more depressions are etched in an exposed surface of asemiconductor substrate or film, backfilled with an electricallyconductive material, and polished back or “planarized” to be even (i.e.,substantially coplanar) with respect to the exposed surface of thesubstrate or film.

As used herein, the term “depression” includes troughs, channels, vias,holes and other depressions in or through a material layer formed upon asemiconductor substrate. For instance, depressions may be used to defineelectrically conductive pathways that carry electronic signals betweenone region of a semiconductor device structure and another regionthereof, and between regions within the semiconductor device structureand external contacts associated therewith, as well as providing power,ground, and bias to integrated circuitry of the semiconductor devicestructure. Such electrically conductive pathways may include, withoutlimitation, depressions used to define traces or lines for signal lines,power and ground lines, and the like.

FIGS. 1A-1E schematically depict a conventional damascene processsequence for creating elongated conductive elements in the form oftraces 26 in an interlevel dielectric layer 14. It will be understood bythose of ordinary skill in the art that, while the process depictedillustrates formation of a plurality of generic conductive traces 26,such traces may be typically utilized for signal lines, power lines andground lines, etc.

Referring to FIG. 1A, a cross-sectional view of a first intermediatestructure 10 in the fabrication of a semiconductor device structure 24having a plurality of traces 26 in the interlevel dielectric layer 14thereof is illustrated. The first intermediate structure 10 includes aninterlevel dielectric layer 14, e.g., thermally grown silicon dioxide(SiO₂), which resides on a semiconductor substrate 12, such as a siliconwafer. It will be understood by those of ordinary skill in the art thatthe figures presented in conjunction with this description are not meantto be actual cross-sectional views of any particular portion of anactual semiconductor device, but are merely representations employed tomore clearly and fully depict the conventional process sequence thanwould otherwise be possible. Elements common between the figures maymaintain the same numeric designation.

A photoresist layer 16, comprising a conventional photoresist material,is disposed atop the interlevel dielectric layer 14 and one or moretrace precursors in the form of trace depressions 18 are patterned inthe photoresist layer 16 using conventional photolithography techniquescomprising selective masking, exposure and development. The patternedtrace depressions 18 may be of any shape or configuration including, butnot limited to, circles, ovals, rectangles, elongated slots and thelike.

As shown in FIG. 1B, the interlevel dielectric layer 14 is subsequentlyetched using the photoresist layer 16 as a mask so that the patternedtrace depressions 18 are extended into the interlevel dielectric layer14. Such etching processes are known to those of ordinary skill in theart and may include, without limitation, reactive ion etching (RIE) oran oxide etch. As shown in FIG. 1C, the photoresist layer 16 issubsequently removed by a conventional process, such as a wet-stripprocess, a tape lift-off technique, or combinations thereof, creating asecond intermediate structure 20.

As shown in FIG. 1D, an electrically conductive material 22, (e.g.,tungsten) is subsequently blanket deposited over the interleveldielectric layer 14 such that the trace depressions 18 are filledtherewith. The electrically conductive material 22 is then planarizedusing, e.g., a mechanical abrasion technique, such as chemicalmechanical planarization (CMP), to isolate the electrically conductivematerial 22 in the trace depressions 18, as illustrated in FIG. 1E.Thus, a semiconductor device structure 24 including a plurality oftraces 26 in the interlevel dielectric layer 14 thereof is fabricated.

For forming more complex electrically conductive pathways, for instance,those in which both an elongated conductive element (e.g., a trace) andone or more discrete, vertically extending conductive structures (e.g.,vias, contacts) are to be defined in a single interlevel dielectriclayer, a dual damascene process may be utilized. FIGS. 2A-2I illustratea conventional dual damascene process sequence. Referring to FIG. 2A, across-sectional view of a first intermediate structure 10′ in thefabrication of a semiconductor device structure 24′ (FIG. 2I) having aplurality of traces 26′ (FIG. 2I) and a plurality of conductor-filledvias 32 (FIG. 2I) in the interlevel dielectric layer 14′ thereof isillustrated. The first intermediate structure 10′ includes an interleveldielectric layer 14′, e.g., thermally grown SiO₂, which resides on asemiconductor substrate 12′, such as a silicon wafer. A mask layer 28having a plurality of trace precursors in the form of trace depressions18′ patterned therein, is disposed atop the interlevel dielectric layer14′. The patterned trace depressions 18′ may be of any shape orconfiguration including, but not limited to, circles, ovals, rectangles,elongated slots and the like.

As shown in FIG. 2B, a photoresist layer 16′, formed from a conventionalphotoresist material, is subsequently deposited atop the mask layer 28such that the patterned trace depressions 18′ are filled therewith.Next, as shown in FIG. 2C, conventional photolithography in the form ofselective masking, exposure and development of photoresist layer 16′ isperformed on the photoresist layer 16′ to form a patterned photoresistlayer 16″ having a plurality of vias 30 patterned therein which alignwith the trace depressions 18′ of the mask layer 28.

Referring to FIG. 2D, the interlevel dielectric layer 14′ issubsequently etched (e.g., by way of RIE) through the patternedphotoresist layer 16″. The pattern of vias 30 is accordingly extendedinto the upper portion of the interlevel dielectric layer 14′.

As shown in FIG. 2E, the patterned photoresist layer 16″ is subsequentlyremoved, forming a second intermediate structure 20′. Thereafter, theinterlevel dielectric layer 14′ is etched using the mask layer 28 withthe patterned trace depressions 18′ therein and the upper portion of theinterlevel dielectric layer 14′ with the vias 30 therein as a mask. Theresult is shown in FIG. 2F, wherein the desired trace pattern isextended into the upper portion of the interlevel dielectric layer 14′and the vias 30 in the upper portion of the interlevel dielectric layer14′ are concurrently extended into the lower portion of the interleveldielectric layer 14′.

Subsequently, as shown in FIG. 2G, the mask layer 28 is removed by aconventional process to create a third intermediate structure 34. Anelectrically conductive material 22′, e.g., tungsten, is then blanketdeposited over the interlevel dielectric layer 14′ such that the tracedepressions 18′ and vias 30 are filled therewith, as shown in FIG. 2H.The electrically conductive material 22′ is then planarized using, e.g.,a mechanical abrasion technique such as chemical mechanicalplanarization (CMP), to isolate the electrically conductive material 22′in the vias 30 and trace depressions 18′. The result of planarization isillustrated in FIG. 2I. Thus, a semiconductor device structure 24′having a plurality of traces 26′ and a plurality of conductor-filledvias 32 defined in a single interlevel dielectric layer 14′ thereof isfabricated.

Further methods of forming damascene and dual damascene structures areknown. For instance, U.S. Pat. No. 6,495,448 describes an additionalprocess for forming a dual damascene structure. However, all suchconventional methods include one or more photolithography processingacts which significantly impact the cost of manufacturing semiconductordevice structures. Further, elongated conductive elements, such astraces, and discrete conductive structures, such as vias, contacts orbond pads, must be created during separate and distinct processing acts,again increasing the cost and complexity of manufacture.

Accordingly, a method of forming elongated conductive elements anddiscrete conductive structures in a semiconductor substrate or film thatutilizes fewer process acts than conventional processing techniques,uses less material than conventional processing techniques, or may beperformed more quickly or more efficiently than conventional processingtechniques would be desirable.

U.S. Pat. No. 6,107,109 to Akram discloses a method for fabricating astraight line electrical path from a conductive layer within asemiconductor device to the backside of a semiconductor substrate usinga laser beam is disclosed. The method includes forming an openingthrough a substrate to electrically connect external contacts engaged ona face side thereof to the back side of the substrate. The opening isperpendicular to both the face side and back side of the substrate. Inone embodiment, the openings are formed using a laser ablation process.

U.S. Pat. No. 6,114,240 discloses a method for laser ablation to formconductive vias for interconnecting contacts (e.g., solder balls, bondpads and the like) on semiconductor components. In the described method,a laser beam is focused to produce vias having a desired geometry, e.g.,hourglass, inwardly tapered, or outwardly tapered.

U.S. Pat. No. 6,696,008 to Brandinger discloses a maskless patterningapparatus which allows for laser beam ablation of one or more layers ofmaterial while not etching an underlying different material layer. Theapparatus also performs a monitoring function during ablation todetermine when to terminate the ablation process.

U.S. patent application Ser. No. 10/673,692 filed Sep. 29, 2003, nowU.S. Pat. No. 7,364,985, issued Apr. 29, 2008, and entitled “METHOD FORCREATING ELECTRICAL PATHWAYS FOR SEMICONDUCTOR DEVICE STRUCTURES USINGLASER MACHINING PROCESSES,” assigned to the assignee of the presentinvention and the disclosure of which is incorporated, in its entirety,by reference herein, discloses a method of laser ablating electricallyconductive pathways in a semiconductor substrate or in a film disposedthereon.

Another aspect of conventional semiconductor device fabrication pertainsto flip-chip assemblies, wherein a semiconductor die is attached by itsactive surface to a carrier substrate. Conventionally, a dielectricunderfill material, generally an epoxy adhesive, is applied between asurface of an individual semiconductor die and a substrate to which itis (already) electrically attached (i.e., by solder balls, bumps, etc.).The underfill material flows, in liquid form, between the semiconductordie and the carrier substrate, securing and stabilizing thesemiconductor die to the carrier substrate.

Conventional dispensing of underfill material may be accomplished via aheated dispensing needle. The dispensing needle is precisely positionedwith respect to the semiconductor die and package, because the accuracyof such positioning may greatly affect the resulting performance of thechip. For example, if the dispensing needle is too far from thesemiconductor die during dispensing, the space between the semiconductordie and the substrate may not be adequately filled with the underfillmaterial, leading to air voids that can affect performance of thesemiconductor die in terms of shorting and environmental degradation. Inaddition, the dispensing rate and viscosity of the underfill materialmay be important as affecting uniform filling.

In view of the foregoing, a laser ablation processing technique whichmay be used for the formation of elongated conductive elements, e.g.,traces and the like, in a film, such as a dielectric film on the surfaceof a semiconductor device or a wafer or other bulk substrate on which aplurality of semiconductor devices are fabricated, would beadvantageous. Further, a technique wherein a plurality of differentelongated conductive elements and discrete conductive structures may bedefined in a single layer (e.g., a film) substantially simultaneouslywould be desirable. In addition, improved methods for providing anunderfill structure for a semiconductor die attached to a carriersubstrate would be beneficial.

BRIEF SUMMARY OF THE INVENTION

The present invention, in one embodiment, relates to a method forforming at least one conductive element in a dielectric layer formedupon a semiconductor substrate. Particularly, such a method may includeproviding a semiconductor substrate having a surface and forming aplurality of semiconductor dice on the surface of the semiconductorsubstrate. Further, a dielectric layer may be formed over the pluralityof semiconductor dice on the surface of the semiconductor substrate. Atleast one depression may be laser ablated in the dielectric layer and anelectrically conductive material may be deposited at least partiallyinto the at least one depression.

Another aspect of the present invention relates to a method forassembling a semiconductor die to a carrier substrate. Morespecifically, a semiconductor die may be provided having an activesurface and a plurality of bond pads thereon. Also, a carrier substratemay be provided having a plurality of terminal pads on a surfacethereof. An underfill or other dielectric layer may be formed over theplurality of bond pads of the semiconductor die and at least onedepression may be laser ablated substantially through the dielectriclayer for electrically accessing at least one of the plurality of bondpads of the semiconductor die. Further, a conductive material may bedeposited at least partially into the at least one depression and the atleast one depression of the semiconductor die may be positionedproximate to a respective at least one of the plurality of terminal padsof the carrier substrate so as to effect electrical communicationtherebetween.

A further aspect of the present invention relates to a method forassembling a semiconductor die to a carrier substrate. Namely, asemiconductor die may be provided having an active surface and aplurality of bond pads thereon and a carrier substrate may be providedhaving a plurality of terminal pads on a surface thereof. Also, anunderfill or other dielectric layer may be formed over the plurality ofbond pads of the semiconductor die and at least one depression may belaser ablated substantially through the dielectric layer forelectrically accessing at least one of the plurality of bond pads of thesemiconductor die. A conductive material may be deposited at leastpartially into the at least one depression. Also, the at least onedepression of the semiconductor die may be positioned proximate to arespective at least one of the plurality of terminal pads of the carriersubstrate so as to enable electrical communication therebetween and thesemiconductor die may be affixed to the carrier substrate. At least oneof the dielectric layer and the conductive material may be at leastpartially melted to affix the semiconductor die to the carriersubstrate. At least one of the dielectric layer and the conductivematerial may remain substantially solid during affixing thesemiconductor die to the carrier substrate.

The methods of the present invention may be effected at the wafer orother bulk substrate level using a plurality of unsingulatedsemiconductor dice and, where applicable, a like plurality ofunsingulated carrier substrates, followed by singulation ofsemiconductor dice with associated carrier substrates.

Other features and advantages of the present invention will becomeapparent to those of skill in the art through consideration of theensuing description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIGS. 1A-1E are cross-sectional views schematically illustrating aconventional method of forming a damascene structure;

FIGS. 2A-2I are cross-sectional views schematically illustrating aconventional method of forming a dual damascene structure;

FIGS. 3A-3E are cross-sectional views schematically illustrating amethod in accordance with the present invention for forming conductiveelements (e.g., conductive traces or vias) in a dielectric layerdisposed upon a semiconductor substrate (e.g., a silicon wafer);

FIG. 3F is a top plan view of a semiconductor device having a pluralityof filled elongated conductive elements in a semiconductor substratethereof;

FIG. 4 is a top elevation view schematically illustrating a workingfield of a laser beam apparatus in accordance with the present inventionfor forming elongated conductive elements in a polymer layer formed upona semiconductor substrate;

FIGS. 5A-5D are cross-sectional views schematically illustrating amethod in accordance with the present invention for forming conductiveelements (e.g., conductive traces or vias) in a dielectric layerdisposed upon a semiconductor substrate semiconductor substrate;

FIG. 6A is a perspective view of a semiconductor die including ablanket-coated underfill material deposited on the active surfacethereof;

FIGS. 6B-6D are cross-sectional views schematically illustrating amethod in accordance with the present invention for forming underfillstructures by way of laser ablation in semiconductor substrate;

FIGS. 7A-7C are cross-sectional views schematically illustrating amethod in accordance with the present invention for assembling asemiconductor die as shown in FIG. 6D to a carrier substrate; and

FIG. 8 schematically depicts a wafer-level assembly of a plurality ofunsingulated semiconductor dice to a like plurality of unsingulatedcarrier substrates.

DETAILED DESCRIPTION OF THE INVENTION

It should be understood that the figures presented in conjunction withthis description are not meant to be actual cross-sectional views of anyparticular portion of an actual substrate or semiconductor device, butare merely representations employed to more clearly and fully depict theprocess of the invention than would otherwise be possible. Furthermore,the particular embodiments described hereinbelow are intended in allrespects to be illustrative rather than limiting. Other and furtherembodiments will become apparent to those of ordinary skill in the artto which the present invention pertains without departing from itsscope.

The present invention relates to a method for creating depressions in adielectric layer or film formed on a surface of a semiconductorsubstrate using laser ablation processes. The depressions may defineconductive traces or lines for signal lines, power and ground lines, andother elongated conductive elements utilized for defining electricalpathways in a semiconductor device. The method of the present inventionmay require fewer processing acts than conventional mask and etchtechniques and may enable the creation of lines or traces substantiallysimultaneously with discrete conductive structures, such as vias,contacts or bond pads. Further, the process may offer a lower costalternative to conventional damascene and dual damascene processes andmay enable the formation of elongated conductive elements and discreteconductive structures of varying shapes to maximize use of the substrateor film. One exemplary application of the technology of the presentinvention is for creating electrically conductive elements alongselected pathways to form a redistribution layer in wafer-levelpackaging.

FIGS. 3A-3F, 4, and 5A-5D illustrate various views of techniquesaccording to the present invention for forming depressions in a film,which depressions define traces or lines for signal lines, power andground lines, other elongated conductive elements or discrete conductiveelements, such as bond pads, contacts or vias in semiconductor devicestructures. It should be understood and appreciated that the methods andstructures of the present invention described herein do not encompasscomplete processes for manufacturing semiconductor device structures.Rather, the process acts and structures described herein pertain tofacilitating an understanding of the methods of the present invention.Further, the omitted portions of the complete processes for fabricatingsemiconductor device structures are well known to those of ordinaryskill in the art.

Referring to FIGS. 3A-3E, acts in an exemplary method according to thepresent invention for fabricating a semiconductor device structure 100having elongated conductive elements in the form of a trace 102A and avia 102B in a dielectric layer 107 formed upon a semiconductor substrate104 are illustrated.

It will be understood and appreciated by those of ordinary skill in theart that while the process depicted illustrates formation of a singletrace 102A and a single via 102B, the process sequence illustrated mayalso be utilized for the formation of a plurality of elongatedconductive elements or a plurality of discrete conductive elements aswell. Put another way, generally, the present invention encompasses amethod of forming at least one conductive element in a dielectric layerformed upon a semiconductor substrate. The at least one conductiveelement may comprise at least one elongated conductive element (e.g., atrace), at least one discrete conductive element (e.g., a via or bondpad), or combinations thereof, without limitation.

With initial reference to FIG. 3A, a cross-sectional view of anintermediate structure 106 in the fabrication of a semiconductor devicestructure 100 (FIGS. 3E and 3F) is depicted. Intermediate structure 106comprises a dielectric layer 107 formed upon a semiconductor substrate104. As used herein, the term “semiconductor substrate” includes asemiconductor wafer or other substrate comprising a layer ofsemiconductor material, such as a silicon wafer, a silicon on insulator(“SOI”) substrate such as a silicon on sapphire (“SOS”) or a silicon onglass (“SOG”) substrate, an epitaxial layer of silicon on a basesemiconductor foundation, and other semiconductor materials including,but not limited to, silicon-germanium, germanium, gallium arsenide andindium phosphide.

Accordingly, a plurality of semiconductor dice may be formed on thesurface of the semiconductor substrate and the dielectric layer may beformed over the plurality of semiconductor dice on the surface of thesemiconductor substrate.

Generally, exemplary materials that may comprise dielectric layer 107include, for example, a polymer, an oxide, a photopolymer, athermoplastic, a glass, and a thermoset plastic. More specifically, forexample, exemplary materials for comprising dielectric layer 107 mayinclude, for example, a spin-on-glass (SOG), a thermal oxide, PARYLENE™polymer, a low silane oxide (LSO), a pulse deposition layer comprisingaluminum rich oxide, silicon dioxide, silicon nitride, siliconoxynitride, borophosphosilicate glass (BPSG), phosphosilicate glass(PSG), borosilicate glass (BSG), or any dielectric material having a lowdielectric constant known in the art. Exemplary thermoplastics that maycomprise dielectric layer 107 include, but are not limited to,polyester, polysulfone, polyetheretherketone, polyimide, polyaryleneether ketone, Vacrel, bisbenzocyclobutene, or polymethylmethacrylate(when cured). Further, adhesives such as epoxies, phenolics, acrylics,cyanoacrylates, and methacrylates may comprise dielectric layer 107. Asknown in the art, the dielectric layer 107 may be applied to asemiconductor substrate by, for example, spin coating, doctor bladecoating, screen-printing, or film transfer techniques.

In one example, it may be desirable that dielectric layer 107 comprise aphotopolymer applied to semiconductor substrate 104 in a flowable statefor example, by spin-coating and curing, en masse, the entire layer ofthe photopolymer residing on semiconductor substrate 104 to formdielectric layer 107 in response to exposure to a UV light or heat. Putanother way, curing of dielectric layer 107 to a substantially solidstate may be effected substantially en masse or substantially as a wholesubsequent to deposition thereof by broad-source UV light in a chamber,thermal cure in an oven, or combinations thereof. In this manner,dielectric layer 107 may be formed in a minimal amount of time.Alternatively, in another example, dielectric layer 107 may be formedupon a surface of semiconductor substrate 104 by a dry film process, asknown in the art.

As shown in FIGS. 3A-3E, another layer of dielectric or insulatingmaterial 107B (such as silicon dioxide (SiO₂), silicon nitride (Si₃N₄),or PARYLENE™ polymer) may be optionally deposited or grown over thesurface of the semiconductor substrate 104 prior to forming a dielectriclayer 107A, if desired. Such a passivation layer may be formed over bondpads of semiconductor dice on a wafer and may be removed to expose thebond pads during the laser ablation process implemented in accordancewith the present invention, eliminating a conventional etch step nowemployed to do so. The two layers of dielectric material 107A and 107Bjointly form dielectric layer 107.

Further, a desired pattern of at least one conductive element precursormay be formed in the dielectric layer 107. Particularly, depressions108A and 108B may be formed in dielectric layer 107 formed upon thesemiconductor substrate 104 using a laser beam 110, as shown in FIG. 3B.In practice, one may place a semiconductor wafer, or other suitablesemiconductor substrate 104, on a chuck or platen of a suitable laserablation apparatus. The desired pattern of depressions 108A and 108B onsemiconductor substrate 104 may be stored in a software programassociated with the laser ablation apparatus such that upon activationthereof, the desired pattern may be ablated in the surface of thedielectric layer 107. In doing so, the laser beam 110 may rapidlytraverse, substantially simultaneously, the surface of the dielectriclayer 107, or may pause briefly in those locations where depressions108A and 108B are desired and remain for a longer period of time atlocations wherein relatively deeper depressions such as depression 108Bare to be formed. In the presently preferred embodiment, the method ofthe present invention may be typically carried out at the wafer level.

Explaining further, at the wafer level, a laser ablation apparatus maybe configured with a “working field” (i.e., an area within which thelaser may effectively ablate) which encompasses a plurality ofsemiconductor dice formed upon a semiconductor wafer. More specifically,FIG. 4 shows a semiconductor wafer 200 in a top elevation view includinga plurality of semiconductor dice 202 formed thereon. Further, workingfield 210 is shown in FIG. 4 as a substantially square area of thesemiconductor wafer 200 and encompasses a plurality of semiconductordice 202. However, working field 210 may be shaped and sized accordingto the capabilities and constraints of the apparatus employed togenerate, focus and aim the laser beam for laser ablation, withoutlimitation.

Accordingly, at least one trace depression may be formed within adielectric layer disposed over each of the plurality of semiconductordice 202 within the working field 210 of the laser ablation apparatussubstantially simultaneously. Such a method may increase throughput of amanufacturing process. Of course, the present invention contemplatesthat the size of the working field of the laser apparatus may be limitedby the present state of the art optics and related technology and,therefore, will increase in the future as the optics and relatedtechnologies advance. However, it should be understood that the workingfield 210 and semiconductor dice 202 depicted in FIG. 4 are merelyillustrative, and should not be construed as limiting.

Commercially available laser ablation apparatus for use in semiconductordevice manufacturing may have a minimum width or footprint of a laserbeam 110 of approximately 15 microns, or smaller. Accordingly, thetechnology of the present invention enables the formation of depressions108A and 108B having a lateral dimension as small as approximately 15microns, or smaller, and a shape suitable to define a desired pattern.For example, one suitable, commercially available, laser ablationapparatus, which comprises a 355 nm wavelength UV YAG laser, is ModelNo. 2700 manufactured by Electro Scientific Industries, Inc., ofPortland, Ore. Another suitable, commercially available, laser ablationapparatus is manufactured by General Scanning of Sommerville, Mass. andis designated as Model No. 670-W. Yet another suitable, commerciallyavailable, laser ablation apparatus is manufactured by Synova S.A. ofLausanne, Switzerland.

Referring now to FIG. 3B, a representative laser fluence (i.e., quantityof incident radiation) of laser beam 110 for forming the depressions108A and 108B within dielectric layer 107 may be from about 2 to about10 watts/per unit area of the laser beam spot size and may have a pulseduration of between about 20-25 nanoseconds (NS), and a repetition rateof up to several thousand pulses per second. The wavelength of the laserbeam 110 may be a known wavelength for forming a laser such as a UVwavelength (e.g., 355 nm), a green wavelength (e.g., 1064 nm-532 nm), oranother wavelength, without limitation. By way of example, the width ofthe depressions 108A and 108B may be between about 15 microns to about 2mils or greater.

It will be understood and appreciated by those of ordinary skill in theart and the present invention contemplates that the footprint of thelaser beam 110 may be limited by the optics technology employedtherewith and the wavelength of the light comprising the laser beam 110.Thus, as optical technology advances, the minimum footprint of the laserbeam 110 may correspondingly become reduced in dimension, such thatdepressions 108A and 108B having increasingly smaller dimensions may beformed utilizing the technology of the present invention.

A laser ablation process of the present invention may be employed toform depressions 108A and 108B, which taper inwardly as the depth of thedielectric layer 107 increases. As shown in FIG. 3B, depression 108A mayextend into the dielectric layer 107, from surface 103 thereof to adistance less than the thickness thereof or may extend through the fullthickness of the dielectric layer 107. Depression 108B, similarly, mayextend into the dielectric layer 107, from surface 103 thereof, throughthe full thickness of the dielectric layer 107 so as to expose at leasta portion of a bond pad 109 formed on the active surface of thesemiconductor substrate 104. Accordingly, each of trace depressions 108Aand 108B may extend to a suitable distance into the dielectric layer 107for forming a respective conductive element, such as a conductive traceor a conductive via.

Optionally, subsequent to laser ablating depressions 108A and 108B andas shown in FIG. 3C, the dielectric layer 107 may be etched to clean thedepressions 108A and 108B and to smooth the cross-sectional shapethereof. Etching in this manner may remove by-products of the laserablation process as well as a so-called “heat-affected zone” (HAZ),which may extend within the remaining dielectric layer 107. In addition,etching may accentuate or alter the laser-ablated shape(s) of thedepressions 108A and 108B.

Generally, the present invention contemplates that anisotropic andisotropic etching processes as known in the art may be employed, suchas, for instance, wet etching and dry etching may be employed inimplementing the present invention. More specifically, by way of exampleand not by limitation, plasma etching, magnetic ion etching, ion beametching, reactive ion etching (RIE), ion beam milling, reactive ion beametching, magnetically enhanced reactive ion etching, ion milling,electron cyclotron resonance, plasma enhanced reactive ion etching,chemical dry etching, chemical etching in a plasma, chemical-physicaletching, or chemical wet etching may be employed for cleaning or furthershaping of depressions 108A and 108B. Of course, the etching process andmaterials may be selected and tailored according to the materialcomprising dielectric layer 107 within which depressions 108A and 108Bare formed.

In addition, dry etch techniques may exhibit etching in a substantiallyanisotropic fashion. This means that the dielectric layer 107 may beetched primarily in a substantially transverse or perpendiculardirection relative to a planar surface (e.g., surface 103) thereof.Thus, such dry etch techniques may be capable of defining depressions orcavities with substantially vertical sidewalls and, therefore, mayfurther define at least a portion of depressions 108A or 108B. Due to atrend in semiconductor fabrication processes toward decreased dimensionsof structures on semiconductor devices, dry etching may be desirable fordefining structures upon semiconductor devices.

An electrically conductive material 112 may, subsequent to formation andoptional cleaning of the depressions 108A and 108B, be blanket coatedover the dielectric layer 107 using a suitable deposition process suchthat the depressions 108A and 108B are at least partially filledtherewith, as shown in FIG. 3D. Suitable deposition processes mayinclude, by way of example and not limitation, plating, soldering (e.g.,wave soldering), atomized nanoparticle deposition, chemical vapordeposition (CVD), metallorganic chemical vapor deposition (MOCVD),plasma enhanced chemical vapor deposition (PECVD), physical vapordeposition (sputtering), and the like.

The electrically conductive material 112 may comprise a metal including,without limitation, aluminum, titanium, nickel, iridium, copper, gold,tin, tungsten, silver, platinum, palladium, tantalum, molybdenum, or analloy of these metals. Solders, such as tin/lead solders andsilver-containing solders, may be particularly useful in implementationof some embodiments of the present invention, as discussed in furtherdetail below. Alternatively, the electrically conductive material 112may comprise a conductive polymer, such as a metal-filled silicone, or aconductive or conductor-filled epoxy. Suitable conductive polymers aresold, for instance, by Epoxy Technology of Billerica, Mass. For example,Epoxy Technology commercially provides a conductive polymer designated“E3114-5.” Further suitable conductive polymers include, withoutlimitation, those sold by A.I. Technology of Trenton, N.J.; Sheldahl ofNorthfield, Minn.; and 3M of St. Paul, Minn. A conductive polymer may bedeposited in the depressions 108A and 108B as a viscous material andsubsequently cured as required and may be applied by a dispensingnozzle, squeegee (e.g., screen-printing), by spin-coating, or asotherwise known to those of ordinary skill in the art. In a furtherembodiment, the electrically conductive material 112 may compriseconductive nanoparticles in an organic carrier, which may be driven offby heating after deposition.

Alternatively, electrically conductive material 112 may be depositedwithin at least a portion of each of depressions 108A and 108B by way ofso-called “maskless mesoscale materials deposition” (M3D). Suchdeposition may be selectively controlled, so that conductive material isdeposited substantially within depressions 108A and 108B and not uponthe entire surface of dielectric layer 107.

For instance, during a maskless mesoscale materials deposition, amaterial may be aerosolized by using an ultrasonic transducer or apneumatic nebulizer. Then, the aerosol stream may be focused using aflow guidance deposition head, which forms an annular, coaxial flowbetween the aerosol stream and a sheath gas stream. Further, patterningmay be accomplished by moving the substrate or deposition head relativeto one another. The deposited electrically conductive material 112 maybe subsequently heated to form a substantially dense electricallyconductive material 112. For instance, the electrically conductivematerial 112 may be heated in an oven or by exposure to a laser beam.Commercially available maskless mesoscale materials deposition apparatusare produced by Optomec of Albuquerque, N. Mex.

Next, as shown in FIG. 3E, if a blanket deposition of electricallyconductive material 112 has been effected as depicted in FIG. 3D, theelectrically conductive material 112 overlying surface 103 may beplanarized using, e.g., a mechanical abrasion technique, such aschemical mechanical planarization (CMP), to electrically isolate theelectrically conductive material 112 in each of depressions 108A and108B from one another or from other electrically conductive elements.

Alternatively, if conductive material is deposited only substantiallywithin each of the depressions 108A and 108B, or is otherwise suitablyelectrically isolated, such planarization may be unnecessary. Forinstance, if the depressions 108A and 108B are suitably sized inrelation to the resolution and precision with which maskless mesoscalematerials deposition may be performed, electrically conductive material112 may be deposited selectively within at least a portion of each ofdepressions 108A and 108B. Not substantially filling depressions 108Aand 108B may be preferred for avoiding the requirement for subsequentplanarization of electrically conductive material 112 (e.g., makingelectrically conductive material 112 substantially coplanar in relationto surface 103). Of course, selective deposition processes as known inthe art, such as plating through a mask may be utilized for depositingelectrically conductive material 112 within at least a portion of eachof the depressions 108A and 108B.

The above-described method may result in a semiconductor devicestructure 100 which includes conductive traces 102A and conductive via102B in the dielectric layer 107 thereof, as shown in FIG. 3F. Thus, asshown in FIGS. 3E and 3F, conductive trace 102A may be configured as anelongated conductive trace while conductive via 102B may be configuredas a combination of a conductive via (extending from bond pad 109) andan elongated conductive trace extending across the surface ofsemiconductor device structure 100. Of course, it should be appreciatedthat elongated conductive via 102B may be, alternatively, configuredsolely as a conductive via as shown in FIG. 3F in broken lines as 102B′or solely as an elongated conductive trace, without limitation.

Thus, methods of the present invention may be used to form depressions,such as troughs, channels, vias, or holes, which may be used to defineelectrical elements that carry electronic signals between one region ofa semiconductor device structure and another region thereof, and betweenregions within the semiconductor device structure and external contactsassociated therewith, or providing power, ground, and bias to integratedcircuitry of the semiconductor device structure.

The method of the present invention may require substantially fewerprocessing acts than conventional mask and etch techniques and may offera lower cost alternative in comparison to conventional processes.Further, the method of the present invention may enable the formation ofelongated conductive elements of varying shapes, patterns, sizes anddepths. Such flexibility may be useful for maximizing the availablesurface area, or “real estate,” of the semiconductor device structure100. Still further, the above-described method may provide a simpleprocess for altering a desired electrical pattern, prior to ablation, asa new pattern merely must be programmed into the laser ablationapparatus. Thus, in contrast to conventional resist and etch processes,no new masks are required in accordance with the present invention whena new pattern is desired. Thus, a process according to the presentinvention may be easier and more convenient for modifying trace designthan conventional mask and etch techniques.

It will be understood by those of ordinary skill in the art that thismethod of the present invention may be used to substantiallysimultaneously ablate a plurality of conductive elements (e.g., tracesor vias) within a dielectric layer formed over a surface of asemiconductor structure. As used herein, the terms “substantiallysimultaneously” and “substantially concurrently” are interchangeable andare used to indicate a relatively rapid traversal of the laser beam overthe surface of the desired dielectric layer.

In another aspect of the present invention, laser ablation may be usedto form at least one depression which does not, initially, communicatewith a bond pad formed on the semiconductor substrate. Rather, thedepression defining at least one trace or via may be proximate to a bondpad so that subsequent etching exposes at least a portion of a bond padof the semiconductor substrate. Such a method may reduce or preventheat, debris, or other undesirable effects from the laser ablationprocess from influencing the bond pad. Accordingly, such a method mayavoid deleterious effects, if any, of employing laser ablation to exposeat least a portion of a bond pad.

In further detail, FIG. 5A shows an intermediate structure 115 includingdepressions 116B which are laser ablated to a degree so as to formsurfaces 119 in dielectric layer 107 proximate to bond pads 109,respectively, of semiconductor substrate 104. Put another way, arelatively small depth of the dielectric layer 107 remains over the bondpads 109 subsequent to the laser ablation of depressions 116B.

Further, intermediate structure 115 as shown in FIG. 5A may be etched toexpose at least a portion of each of bond pads 109, further shapedepressions 116B, remove the HAZ, or combinations thereof. Any of theabove-mentioned etching processes described, as described above.

Thus, subsequent to etching the semiconductor substrate to form thestructure shown in FIG. 5A, at least a portion of the thin depth ofdielectric layer 107 remaining over the bond pads 109, may be removed,thus exposing at least a portion of each of the bond pads 109,respectively, and forming depressions 118B as shown in FIG. 5B. Further,an electrically conductive material 112, as described hereinabove, maysubsequently be deposited such that depressions 118B are at leastpartially filled therewith, as shown in FIG. 5C.

For clarity, any of the above-described processes and materialspertaining to electrically conductive material 112 may be employed withrespect to deposition of electrically conductive material 112 withindepressions 118B. For instance, a conductive polymer or conductivenanoparticles may be deposited within depressions 118B. As a furtheralternative, a maskless mesoscale materials deposition process may beused to deposit conductive material within depressions 118B.

If required by the deposition process employed, the electricallyconductive material 112 overlying the surface 103 of dielectric layer107 as shown in FIG. 5C, may be planarized by employing, for instance, amechanical abrasion technique, such as CMP, to electrically isolate theelectrically conductive material 112 within the depressions 118B. Thus,as shown in FIG. 5D, a semiconductor device structure 120 includingconductive elements 126 and 128 may be formed according to a method ofthe present invention.

The above-described method may substantially avoid damage to bond pads109 associated with exposure thereof via laser ablation alone.Accordingly, such a method may be advantageous for providing electricalaccess to at least one bond pad 109 of a semiconductor substrate or aplurality of bond pads 109 of a semiconductor substrate 104, as shown inFIGS. 5A-5D.

In another aspect of the present invention, a flip-chip package may befabricated utilizing a laser ablation process to form depressions in anunderfill or other dielectric material formed over a plurality of bondpads of a semiconductor die.

More particularly, as shown in FIGS. 6A and 6B, showing a perspectiveview of semiconductor die 400 and a side cross-sectional view thereof,respectively, a dielectric layer 402 may be formed upon an activesurface 403 of a semiconductor die 400, covering the plurality of bondpads 404 thereof. Dielectric layer 402 may comprise, for instance, atleast one of an epoxy resin with or without inert fillers, a polymer, aphotopolymer, a thermoplastic, or a thermosetting resin. The dielectriclayer 402 may be applied in flowable form or as a preformed, dry film.If dielectric layer 402 comprises a thermoplastic or thermosettingmaterial applied in flowable form, it may be baked below its reflow orcure temperature to form a stable film.

Further, as shown in FIG. 6C, a plurality of depressions 408 may beformed into surface 405 of dielectric layer 402 by laser ablationthereof, to expose (or nearly expose) at least a portion of each of bondpads 404, respectively. As described hereinabove with respect to FIGS.3A-3E and FIGS. 5A-5D, laser ablation, etching, or combinations thereofmay be employed to form depressions 408 for allowing, ultimately,electrical communication with a plurality of bond pads 404 of asemiconductor die 400, respectively. More specifically, in one example,laser ablation may expose at least a portion of each of bond pads 404through dielectric layer 402 and, optionally, depressions 408 may becleaned, as by use of an etchant, subsequent thereto. Alternatively,laser ablation may form initial depressions that extend proximate toeach of bond pads 404 and a subsequent etching process may expose atleast a portion thereof, respectively, as well as cleaning thedepressions 408 of debris.

Further, each of the depressions 408 may be sized and configured forultimately accepting a quantity of conductive material therein. As shownin FIG. 6D, electrically conductive material 420 may be deposited atleast partially within each of the plurality of depressions 408 by ascreen-printing process, by blanket deposition followed by planarizationusing one of the previously discussed deposition methods, by the use ofganged dispensing needles, or any other processes as known in the artfor depositing a conductive material within each of the plurality ofdepressions 408. Further, if solder is to be used as electricallyconductive material 420, preformed solder balls or pellets may bedisposed in each of depressions 408, and then reflowed either prior toattachment of semiconductor die 400 to a carrier substrate as discussedin detail below to affix the solder to the semiconductor die 400, andthen a second reflow conducted for attachment to the carrier substrate,or a single reflow conducted during the carrier substrate attach.Additionally, conductive material may be deposited in accordance withany of the above-described methods for depositing electricallyconductive material 112.

For instance, explaining further, processes which move, push, spray, orforce electrically conductive material 420 into each of depressions 408may be utilized. In one example, a screen-printing process (with orwithout a stencil) may be performed for depositing electricallyconductive material 420 (e.g., a conductive paste or ink) at leastpartially within the each of depressions 408 formed in the dielectriclayer 402 according to the present invention.

Optionally, in combination with the above-described processes or otherprocesses as known in the art for depositing electrically conductivematerial 420 within depressions 408, electrically conductive material420 may be vibrated for promoting substantial and uniform filling ofdepressions 408 therewith, or for promoting the distribution (i.e.,spreading) of paste substantially transverse to the direction of anearthly gravitational field. For instance, the present inventioncontemplates that vibration may be communicated to the electricallyconductive material 420 by vibrating the semiconductor die 400, or asotherwise may be effective for causing at least partial filling ofdepressions 408 with electrically conductive material 420. Also,electrically conductive material 420 may be vibrated, such as byapplication of ultrasonic vibrational energy, during disposition thereofat least partially within depressions 408, thereafter, or both duringand after deposition thereof at least partially within depressions 408.

Subsequent to depositing electrically conductive material 420 at leastpartially within depressions 408, a blade or another leveling apparatusmay be employed to planarize or level the upper surface of theelectrically conductive material 420 disposed within depressions 408.Put another way, the upper surface of electrically conductive material420 may be leveled so as to exhibit an upper surface topography, whichis substantially coplanar with respect to the surface 405 of dielectriclayer 402. For instance, the electrically conductive material 420 may beplanarized, if desirable (e.g., if electrically conductive material 420extends beyond surface 405 of dielectric layer 402), by a mechanicalabrasion technique, such as chemical mechanical planarization (CMP), oranother planarization technique as known in the art.

Also, the semiconductor die 400 may be assembled with a carriersubstrate 412 so as to provide electrical communication therebetween, asshown in FIGS. 7A-7C. In further detail, the semiconductor die 400 maybe positioned so that each of the depressions 408 thereof are positionedproximately and in alignment with each of the respective terminal pads416 of the carrier substrate 412. It is further noted that the actsdepicted in FIGS. 6A through 6D may, for economy, desirably be effectedsubstantially simultaneously on a plurality of unsingulated dicecomprising a portion of a larger semiconductor substrate such as asemiconductor wafer or other bulk substrate, and semiconductor dice 400singulated thereafter. It should also be noted that carrier substrate412 may comprise one of a plurality of unsingulated carrier substrates412 of a like number and size to unsingulated semiconductor dice 400.Thus, assembly of semiconductor dice 400 with carrier substrates 412 maybe effected at the wafer or other bulk substrate level, and singulationof semiconductor dice 400, each affixed and electrically connected to acarrier substrate 412, may be effected thereafter. Such an approach isdepicted schematically in FIG. 8, prior to singulation along streets Sbetween adjacent dice.

Conventionally, electrical and mechanical connection between asemiconductor die and a carrier substrate may be accomplished byaffixing the bond pads of a semiconductor die to the terminal pads of acarrier substrate, then applying an underfill material between thesemiconductor die and the carrier substrate. In contrast, according tothe present invention, dielectric layer 402 is present prior toelectrically and mechanically connecting the semiconductor die 400 tothe carrier substrate 412. Therefore, certain advantages may berealized.

In one process according to the present invention, the dielectric layer402 may at least partially melt during bonding of the semiconductor die400 to the carrier substrate 412. Regarding an amorphous material,“melts,” as used herein, denotes a state or condition of a material at atemperature exceeding its glass transition temperature. In anotherprocess according to the present invention, the dielectric layer 402 mayretain a substantially solid state during bonding of the semiconductordie 400 to the carrier substrate 412. In a variation wherein thedielectric layer 402 remains substantially solid during bonding, it maybecome tacky nonetheless to adhere semiconductor die 400 to carriersubstrate 412.

In one example of a process according to the present invention, as shownin FIG. 7A, the semiconductor die 400 (FIG. 6D) may be aligned with andassembled to a carrier substrate 412 to form a semiconductor deviceassembly 410. Where electrically conductive material 420 comprises aconductive paste, such as a solder paste, a reflow process, as known inthe art, may be employed to melt electrically conductive material 420,which, upon solidifying, may affix and electrically connect the carriersubstrate 412 to the semiconductor die 400 by forming conductivestructures 422. Further, the temperature required to melt theelectrically conductive material 420 may also melt or at least partiallymelt the dielectric layer 402. Thus, both electrically conductivematerial 420 and dielectric layer 402 may affix (upon solidification orcuring) the semiconductor die 400 to the carrier substrate 412. Ofcourse, depending on the properties of the electrically conductivematerial 420 and the dielectric layer 402, affixation of each may occurat different temperatures or under different conditions. Such a processmay be advantageous in comparison to conventional underfill processesbecause very little air must be displaced by the dielectric layer 402 tosubstantially completely fill between the semiconductor die 400 and thecarrier substrate 412.

Regarding another example of a process according to the presentinvention, as shown in FIG. 7A, the semiconductor die 400 and carriersubstrate 412 may be aligned and assembled to one another. However, ifthe dielectric layer 402 may remain at least partially solid duringbonding of the semiconductor die 400 to the carrier substrate 412, itmay be preferable to bond (electrically and mechanically) thesemiconductor die 400 to the carrier substrate 412 while the dielectriclayer 402 is under compressive stress.

For instance, as shown in FIG. 7C force F may be applied to thesemiconductor die 400 and carrier substrate 412 which compresses thedielectric layer 402 therebetween during bonding of the semiconductordie 400 to the carrier substrate 412 by melting or curing theelectrically conductive material 420 within each of depressions 408 toform conductive structures 422. Such a process may provide a favorableenvironment for sealing the dielectric layer 402 to the semiconductordie 400. Further, dielectric layer 402 may comprise a resilient orflexible material. Thus, dielectric layer 402 may exhibit a first,uncompressed thickness and, under a force as described above, a second,compressed thickness which is less than the first, uncompressedthickness.

Of course, optionally, external forces may not be applied to thesemiconductor device assembly 410 during affixation of the semiconductordie 400 to carrier substrate 412, so that substantially only the earthlyforce of gravity associated therewith may influence the semiconductordevice assembly 410 during such affixation. In such a configuration, thedielectric layer 402 may provide a desired stand-off gap between thesemiconductor die 400 and the carrier substrate 412.

The present invention also contemplates that the dielectric layer 402may bond the semiconductor die 400 to the carrier substrate 412, whilethe electrically conductive material 420 may be substantially solidduring such affixation. In further detail, for instance, electricallyconductive material 420 may comprise a plated metal, such as copper,which may be planarized (or selectively deposited) to form asemiconductor die 400 including a dielectric layer 402 surrounding solidelements of electrically conductive material 420 as shown in FIG. 6D.Then, the semiconductor die 400 and carrier substrate 412 may be alignedand assembled to one another and heated to at least partially melt thedielectric layer 402. However, the electrically conductive material 420may remain at least partially solid during bonding of the semiconductordie 400 to the carrier substrate 412, becoming merely tacky to providean adhesive effect. Optionally, it may be preferable to force thesemiconductor die 400 toward the carrier substrate 412 while thedielectric layer 402 at least partially melts. Such a configuration mayprovide a compressive stress state within the conductive structures 422within the semiconductor device assembly 410. Thus, summarizing, thepresent invention contemplates flip-chip arrangements wherein at leastone of the dielectric layer and the conductive material may remainsubstantially solid during affixing the semiconductor die to the carriersubstrate 412.

Thus, it will be appreciated by those of ordinary skill in the art thatthe present invention eliminates process acts as employed in the stateof the art, eliminates capital expenditures and materials forphotolithography and dry etching, and produces a high quality,repeatable product that may be quickly and easily modified, as desiredor required. In addition, wafer throughput is increased by eliminationof photolithographic alignment and development requirements, and polymerpull-back issues as experienced in the state of the art photopolymersare eliminated, as (for example) a polyimide used for a dielectric layerin the present invention is cured prior to laser ablation.

The present invention has been described in relation to particular,exemplary embodiments that are intended in all respects to beillustrative rather than restrictive or limiting. It is to be understoodthat the invention defined by the appended claims is not to be limitedby particular details set forth in the above description and that otherembodiments and modifications to the exemplary embodiments will bereadily apparent to those of ordinary skill in the art to which thepresent invention pertains without departing from the spirit and scopethereof.

1. A method for forming at least one conductive element in a dielectriclayer formed upon a semiconductor substrate, comprising: providing asemiconductor substrate; forming a plurality of semiconductor dice on asurface of the semiconductor substrate; forming a first dielectric layerover the plurality of semiconductor dice on the surface of thesemiconductor substrate; forming a second dielectric layer over thefirst dielectric layer; ablating at least one elongate depressionextending into but not through the second dielectric layer and at leastone discrete depression extending through the second dielectric layerand into the first dielectric layer; and depositing an electricallyconductive material at least partially into the at least one elongatedepression and the at least one discrete depression.
 2. The method ofclaim 1, wherein ablating at least one discrete depression extendingthrough the second and into the first dielectric layer comprises laserablating a surface of the first dielectric layer at least proximate to asurface of at least one bond pad of at least one semiconductor die ofthe plurality of semiconductor dice.
 3. The method of claim 2, furthercomprising etching the first dielectric layer at least at a lower extentof the at least one discrete depression to expose at least a portion ofthe at least one bond pad.
 4. The method of claim 1, wherein ablatingthe at least one discrete depression extending through the seconddielectric layer and into the first dielectric layer comprises ablatinga plurality of discrete depressions extending through the seconddielectric layer and into the first dielectric layer.
 5. The method ofclaim 1, wherein forming the first dielectric layer over the pluralityof semiconductor dice on the surface of the semiconductor substratecomprises forming a first dielectric layer including at least one of asilicon dioxide, silicon nitride, or PARYLENE™ polymer.
 6. The method ofclaim 1, wherein forming the second dielectric layer over the firstdielectric layer comprises forming a second dielectric layer includingat least one of a polymer, an oxide, a photopolymer, a thermoplastic, aglass, and a thermosetting plastic.
 7. The method of claim 1, whereindepositing the electrically conductive material at least partially intothe at least one elongate depression and the at least one discretedepression comprises depositing the electrically conductive materialover a surface of the second dielectric layer and at least partiallyinto the at least one elongate depression and the at least one discretedepression and further comprising planarizing the electricallyconductive material at least to the surface of the second dielectriclayer to electrically isolate the electrically conductive material atleast partially within the at least one elongate depression and the atleast one discrete depression.
 8. The method of claim 7, furthercomprising etching the at least one discrete depression in the surfaceof the first dielectric layer to a greater depth subsequent to ablatingand prior to depositing the electrically conductive material over thesurface of the semiconductor substrate.
 9. The method of claim 1,wherein ablating the at least one elongate depression comprises ablatingat least one depression elongated to a length in a directionsubstantially parallel to a surface of the semiconductor substrate inand along the surface of the second dielectric layer, the length of theat least one depression being greater than a width of the at least onedepression.
 10. The method of claim 9, wherein ablating the at least oneelongate depression further comprises ablating at least one discretedepression extending to a greater depth than the at least one elongateddepression.
 11. The method of claim 10, further comprising forming theat least one discrete depression through a portion of a bottom of the atleast one elongated depression.
 12. The method of claim 1, whereinablating the at least one elongate depression comprises ablating atleast one discrete depression through a portion of a bottom of the atleast one elongate depression.
 13. A method for forming at least oneconductive element in a dielectric layer formed upon a semiconductorsubstrate, comprising: providing a semiconductor substrate; forming aplurality of semiconductor dice on a surface of the semiconductorsubstrate; forming a first dielectric layer over the plurality ofsemiconductor dice on the surface of the semiconductor substrate;forming a second dielectric layer over the first dielectric layerablating at least one elongate depression extending into but not throughthe second dielectric layer and at least one discrete depressionextending through a bottom of the at least one elongate depressionthrough the second dielectric layer and into the first dielectric layer;and depositing an electrically conductive material at least partiallyinto the at least one elongate depression and the at least one discretedepression.
 14. The method of claim 13, wherein ablating the at leastone discrete depression through the second dielectric layer and into thefirst dielectric layer comprises laser ablating a surface of the firstdielectric layer at least proximate to a surface of at least one bondpad of at least one semiconductor die of the plurality of semiconductordice.
 15. The method of claim 14, further comprising ablating the atleast one discrete depression extending through a bottom of the at leastone elongate depression through the second dielectric layer and into thefirst dielectric layer to expose at least a portion of the at least onebond pad.
 16. The method of claim 13, wherein ablating the at least oneelongate depression comprises laser ablating a trench for at least oneconductive element elongated to a length in a direction substantiallyparallel to a surface of the semiconductor substrate in and along thesurface of the second dielectric layer, the length of the trench beinggreater than a width of the trench.
 17. The method of claim 13, whereindepositing the electrically conductive material at least partially intothe at least one elongate depression and the at least one discretedepression comprises depositing the electrically conductive materialover a surface of the second dielectric layer and at least partiallyinto the at least one elongate depression and the at least one discretedepression and further comprising planarizing the electricallyconductive material at least to the surface of the second dielectriclayer to electrically isolate the electrically conductive material atleast partially within the at least one elongate depression and the atleast one discrete depression.
 18. The method of claim 17, furthercomprising etching at least one elongate depression of the plurality inthe surface of the dielectric layer to a greater depth subsequent toablating and prior to depositing the electrically conductive materialover the surface of the semiconductor substrate.
 19. The method of claim13, wherein ablating the at least one elongate depression comprisesablating at least one elongated depression extending substantially in amajor plane of the semiconductor substrate.
 20. The method of claim 13,wherein ablating at least one elongate depression extending into but notthrough the second dielectric layer and at least one discrete depressionextending through a bottom of the at least one elongate depressionthrough the second dielectric layer and into the first dielectric layercomprises ablating a plurality of discrete depressions extending througha bottom of the at least one elongate depression through the seconddielectric layer and into the first dielectric layer.
 21. A method forforming a semiconductor device assembly, comprising: providing aplurality of semiconductor dice, each semiconductor dice of theplurality having an active surface and a plurality of bond pads thereon;providing a plurality of carrier substrates, each carrier substrate ofthe plurality having a plurality of terminal pads on a surface thereof;forming a first dielectric layer over the plurality of bond pads of theplurality of semiconductor dice; forming a second dielectric layer overthe first dielectric layer; laser ablating at least one elongatedepression extending into but not through the second dielectric layerand at least one discrete depression extending through the seconddielectric layer and substantially through the first dielectric layerfor electrically accessing at least one of the plurality of bond pads ofthe plurality of semiconductor dice; depositing a conductive material atleast partially into the at least one elongate depression and the atleast one discrete depression; positioning the at least one discretedepression proximate to at least one of the plurality of terminal padsso as to allow direct contact between the conductive material and atleast one of the plurality of terminal pads with electricalcommunication therebetween; and affixing the plurality of semiconductordice to the plurality of carrier substrates.
 22. The method of claim 21,further comprising at least partially melting the conductive materialwithin the at least one discrete depression to form an electricallyconductive structure between the at least one bond pad of the pluralityof bond pads and the at least one terminal pad of the plurality ofterminal pads.
 23. The method of claim 22, further comprisingcompressing the second dielectric layer between the at least onesemiconductor die and the at least one carrier substrate during at leastpartially melting the conductive material.
 24. The method of claim 21,further comprising at least partially melting the second dielectriclayer.
 25. The method of claim 24, further comprising compressing theconductive material between the at least one semiconductor die and theat least one carrier substrate during at least partially melting thesecond dielectric layer.
 26. The method of claim 24, further comprisingaffixing the at least one semiconductor die to the at least one carriersubstrate by at least partially melting the second dielectric layer. 27.The method of claim 21, wherein laser ablating at least one discretedepression extending through the second dielectric layer andsubstantially through the first dielectric layer comprises laserablating a surface of the first dielectric layer proximate to a surfaceof each of the plurality of bond pads of the at least one semiconductordie.
 28. The method of claim 27, further comprising etching the laserablated surface of the at least one discrete depression to expose atleast a portion of the at least one of the plurality of bond pads of theat least one semiconductor die.
 29. The method of claim 21, furthercomprising forcing the at least one semiconductor die toward the carriersubstrate while affixing the at least one semiconductor die to the atleast one carrier substrate.
 30. The method of claim 21, whereinproviding the at least one semiconductor die comprises providing aplurality of semiconductor dice in an unsingulated state on a bulksemiconductor substrate, providing the at least one carrier substratecomprises providing a like plurality of carrier substrates in anunsingulated state comprising a bulk substrate, and further comprisingsingulating semiconductor dice of the plurality, each having a carriersubstrate associated therewith, after affixing the plurality ofsemiconductor dice to the like plurality of carrier substrates.